package Ttt1;

import java.util.Scanner;

class Circle{
    private int radius;

    Circle(){
        this.radius = 2;
        System.out.println("This is a constructor with no para.");
    }

    Circle(int radius){
        if(radius<=0)
            radius = 2;
        this.radius = radius;
        System.out.println("This is a constructor with para.");
    }

    void setRadius(int radius1){
        if(radius1 <= 0)
            radius1=2;
        radius = radius1;
    }

    int getRadius(){
        return radius;
    }

    double getArea(){
        return Math.PI * radius *radius;
    }

    public  String toString(){
        return "Circle [radius=" + radius + "]";
    }

}

public class Main {
    public static void main(String[] args) {
        Scanner reader  = new Scanner(System.in);
        int r2 = reader.nextInt();
        int r3 = reader.nextInt();

        Circle c1 = new Circle();
        System.out.println(c1.toString());
        System.out.printf("%.2f\n",c1.getArea());

        Circle c2 = new Circle();
        System.out.println(c2.toString());
        System.out.printf("%.2f\n",c2.getArea());


        c2.setRadius(r2);
        System.out.println(c2.toString());
        System.out.printf("%.2f\n",c2.getArea());

        Circle c3 = new Circle(r3);
        System.out.println(c3.toString());
        System.out.printf("%.2f\n",c3.getArea());

    }
}
